Where's the Vice President during all of this?

The Speaker of the House introduces the Martian ambassador to a joint session of Congress; the VP and Speaker of the House normally stand/sit side-by-side during Congressional joint sessions. The Vice President's absence could have been for any number of reasons. President Dale's press secretary told him that "for some picky reason the Secret Service didn't want the legislative branch and the executive branch in the same room at the same time;" that could have been the reason for the VP's absence. When President George W. Bush addressed Congress after 9/11, VP Dick Cheney was one of two "designated survivors" which means he would have been taken to an undisclosed location outside of Washington and surrounded by a very high level of security during the President's speech. Considering that the Martians had already killed dozens of people in the Nevada desert, I think it's entirely possible the Secret Service took similar precautions during the Martian Ambassador's visit to the Capitol. I also suppose the VP could have been among those killed in the desert, but that would seem unlikely since I think that if the VP had been there, he or she would have been the first one to greet the Martians, rather than General Casey. At the end of the movie, we see Taffy (President Dale's daughter) executing certain presidential duties, which implies that the Martians wiped out the entire Presidential Line of Succession, of which the Vice President is the highest ranking member (or if anyone in the Presidential Line of Succession survived, they were unable to make it to Washington and present the medals to Richie and Florence Norris in a timely manner).